Never mind the "mommy porn" clucking about "Fifty Shades of Grey." What happens to the electric toothbrush in "Spank!," a stage send-up of the bondage-for-beginners bestseller, ought to have the American Dental Association setting up picket lines outside the Regency Ballroom. That's where "The Fifty Shades Parody" opened Thursday for a weekend run.

No sooner has the naive young heroine started scrubbing her gums than her billionaire sex partner is bearing down on her to demonstrate a more stimulating use for the device. Like every other more or less cylindrical object that crops up in the two-hour production, the toothbrush is a ready phallic stand-in. And who knew that mouthwash was an exchangeable bodily fluid?

That scene is one of the looser, funnier bits in a sketch-style show that struggles with the inherent problem of trying to skewer a book that does a pretty good job of filleting itself. Engrossing and erotic as some readers may find the "Fifty Shades" trilogy to be, it's a pretty safe bet that British writer E.L. James won't supplant Henry James on the depth charts. Others would take a blunter view: The sex scenes may flip your switch and it's all harmless fantasyland fun, but seriously folks, writing this patently, ridiculously bad doesn't come along and sell a gazillion books very often.

The creators of "Spank!," led by head writer and director Jim Millan and a cast of three, are clearly incredulous about it all. But it's only in fits and starts that they turn that attitude into comically productive parody. A lot of the show is a pretty close gloss on the original, including scenes and lines played out much as they are on the page.

'Twilight' fan

Amanda Barker plays the brassy, bawdy author of the books, tapping her characters into being on a computer keyboard. Like James, this housewife wordsmith got her start as a "Twilight" fan fictioneer. That cues up the vampire gags in the show.

Goggle-eyed Michelle Vezilj is the Stepford virgin Tasha, who meets the filthy rich and sexually dominant hero, falls under his spell and signs a lengthy S-and-M deal. "Fifty Shades," as the show observes, is almost as much about contract law as it is about sex. Talk about a turn-on.

Drew Moerlein is the evening's main attraction as smoldering Hugh Hanson, a role that requires him to bump and grind and bare his Chippendale-worthy pecs, sing a ballad about the joys of paddling, play Hugh's entire family, mother and sister included, and embody an Asian spam e-mailer of "boner pills." He makes a good-natured and lively chameleon.

Theater of the absurd

The show scores some decent if easy points about the more ludicrous aspects of the books. Even vacuous Tasha notices how dumb it is that a contemporary college student would never have used a computer until Hugh sends her one. The musical interludes, which include some serious-sex Bach and repurposed Gershwin, Gilbert and Sullivan, and Sondheim, are a deft way of remarking on the absurdity that Tasha is a lover of Thomas Hardy and other finer things.

The opening-night crowd, which appeared to be about 90 percent female, warmed audibly to Moerlein. In many ways "Spank!" is all about the audience. The man of the hour gets them howling every time he undoes a button. Barker reminds them all directly that "Fifty Shades" is an escape hatch from their mundane sex lives and tosses in a pre-49ers Super Bowl cheer for good measure. Vezilj pays several visits to the front rows of the house.

In one of them on Thursday, she had a woman play a doctor, then asked her how big an item it might be safe to use as a sex toy. When the amateur doc indicated a thing the size of a cat, Vezilj let out a mighty meow.